Why the C-130 carrier trials avoided catapults and arresting wires

Did the C-130 carrier trials use catapults or arresting gear, and what were they meant to prove?

No; the stripped aircraft used its own short-field performance to prove an emergency delivery option that was possible but impractical.

The C-130 carrier trials did not use the ship's catapult or arresting wires because neither system was suited to an aircraft of that size. A stripped Hercules instead relied on its own short-takeoff-and-landing performance and the wind generated by the moving carrier. The test asked whether extreme-range carrier onboard delivery remained possible if no better aircraft were available. It showed that the manoeuvre could be done, but only at a level of desperation that made adoption unattractive. The comparison with the even more dramatic short-field performance of the Caribou reinforces that the result came from aircraft characteristics and skilled pilots rather than ordinary carrier equipment.